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Displaying 32451 - 32475 of 73830

Numerical Fluorescence Correlation Spectroscopy for Molecular Dynamics Analyses Under Non-Standard Conditions

June 1, 2007
Author(s)
Michael J. Culbertson, Joshua T. Williams, Wayland Cheng, Dee A. Stults, Emily R. Wiebrach, John J. Kasianowicz, Daniel L. Burden
A major concern in Fluorescence Correlation Spectroscopy (FCS) pertains to the accuracy of standard mathematical models that are used to extract kinetic information from correlated data. The standard equations used in FCS arise from a simple Gaussian model

Observation of the 1 S 0 - 3 P 0 clock transition in 27 Al +

June 1, 2007
Author(s)
Till P. Rosenband, P. O. Schmidt, David Hume, Wayne M. Itano, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Jeroen Koelemeij, James C. Bergquist, David J. Wineland
We report for the first time, laser spectroscopy of the 1S 0 – 3P 0 clock transition in 27Al +. A single aluminum ion and a single beryllium ion are simultaneously confined in a linear Paul trap, coupled by their mutual Coulomb repulsion. This coupling

Optical and Structural Study of GaN Nanowires Grown by Catalyst-Free MBE: (II) Defect-Related Luminescence and Electron-Beam Irradiation Effects

June 1, 2007
Author(s)
Lawrence H. Robins, Kristine A. Bertness, John G. Barker, Norman A. Sanford, John B. Schlager
GaN nanowires grown by catalyst free molecular beam epitaxy were characterized by photoluminescence (PL) and cathodoluminescence (CL) spectroscopy at temperatures from 3 K to 295 K. Both as grown samples, which contained approximately vertically oriented

Quantum key distribution over a 40-dB channel loss using superconducting single-photon detectors

June 1, 2007
Author(s)
Hiroki Takesue, Sae Woo Nam, Qiang Zhang, Robert Hadfield, Toshimori Honjo, Kiyoshi Tamaki, Yoshihisa Yamamoto
We report the first quantum key distribution (QKD) experiment to enable the creation of secure keys over 42 dB channel loss and 200 km of optical fibre. We used the differential phase shift QKD (DPS-QKD) protocol, implemented with a 10-GHz clock frequency

Spotlighting NIST Standard Reference Materials - New Standard Reference Material (SRM) 2585 Organic Contaminants in House Dust to Support Exposure Assessment Measurements

June 1, 2007
Author(s)
Michele M. Schantz, Jennifer M. Lynch, John R. Kucklick, Dianne L. Poster, H M. Stapleton, S S. Vander Pol, Stephen A. Wise
House dust originates from both internal and external sources and has been identified as one of the primary sources of lead exposure for children (http://www.epa.gov/lead). House dust is also a repository for pesticides, flame retardants, and other

Static Calibration and Dynamic Characterization of PMUs at NIST

June 1, 2007
Author(s)
Gerard N. Stenbakken, Thomas L. Nelson
This paper describes the development of two test systems at NIST aimed at improving the calibration and characterization of Coordinated Universal Time (UTC) synchronized electric power instrumentation. Reference to UTC is used to meet the need for precise

Supplement to the 2004 Update of the AAPM Task Group No. 43 Report

June 1, 2007
Author(s)
Mark J. Rivard, Wayne Butler, Larry A. DeWerd, Saiful M. Huq, Geoffrey S. Ibbott, Christopher Melhus, Michael G. Mitch, Ravinder Nath, J Williamson
Since publication of the 2004 update to the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report (AAPM TG-43U1), several new low-energy photon-emitting brachytherapy sources have become available. Many of these sources have

The NIST Calibration Check Standards Database

June 1, 2007
Author(s)
Kevin G. Brady, Frederic J. de Vaulx, Randolph Elmquist
For several years now, NIST has been a leader in the development and use of Information Technology to process calibration information. Beginning in 1996, researchers designed and developed a calibration database, the NIST Information System to Support

Wavelength bistability in two-section mode-locked quantum-dot diode lasers

June 1, 2007
Author(s)
Mingming M. Feng, N. A. Brilliant, Steven T. Cundiff, Richard Mirin, Kevin L. Silverman
We report a two-section mode-locked quantum dot laser with an emission wavelength that is bistable with respect to applied bias on the saturable absorber region. The two stable lasing wavelengths for this device are 1173 nm and 1166 nm with a power

Electrical Characterization of Self-Assembled Monolayers

May 30, 2007
Author(s)
Wenyong Wang, Takhee Lee, Mark Reed
Electrical characterization of alkanethiol self-assembled monolayers (SAMs) has been performed using a nanometer-scale device structure. Temperature-variable current-voltage measurement is carried out to distinguish between different conduction mechanisms

A Theoretical Analysis of Frequency Uncertainty

May 29, 2007
Author(s)
Gianna Panfilo, Thomas E. Parker
In this work we present a preliminary study for the determination of the uncertainty on the frequency in the time measurement. The first part of this paper is dedicated to the theoretical study of the frequency uncertainty applying the law of the

Active Vibration-induced PM Noise Control in Optical Fibers: Preliminary Studies

May 29, 2007
Author(s)
David A. Howe, Archita Hati, Craig Nelson, Jennifer A. Taylor, Neil Ashby
Vibration causes mechanical distortions in fiber-optic transmission lines that induce time (phase) fluctuations. RF systems are increasingly using optical fibers in various ways and must occasionally operate in environments with acoustic and structure-born

Experimental Analysis of Frequency Transfer Uncertainty

May 29, 2007
Author(s)
Thomas E. Parker, Gianna Panfilo
An experimental analysis of frequency transfer uncertainty is carried out. In situations where more than one transfer techniques are available a first difference statistic is used to determine the type and level of the transfer noise for transfer methods

Further Examination of the Injection-Locked Dual Optoelectronic Oscillator

May 29, 2007
Author(s)
Kai Hudek, Archita Hati, W Zhou, David A. Howe, Craig W. Nelson
Optoelectronic oscillators (OEO), utilizing the low loss nature of optical links, can generate oscillations with very high Q values. The long delay line used in the oscillator can, however, support many modes of oscillation. Mode spacing is inversely
Displaying 32451 - 32475 of 73830
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